L 748337 is a selective, competitive β3-AR (β3-adrenoceptor ) antagonist that displays selectivity over β1 and β2 receptors (Ki values are 4.0, 204 and 390 nM for β3-, β2- and β1-adrenoceptors respectively). Inhibits cAMP accumulation in response to isoproterenol (IC50 = 6 nM).
